I may soon need to seek emergency medical help, and was wondering through advice what I should say to them or what kind of specialist I should seek out.

My head is the main concern. I have what feels like a swollen head and a pain that seems to be married to it in my lower left back - below my kidney.

The pain in my lower back when it first started to hurt, it felt like a blood vessel was about to burst (I know this because the pain was in the same rhythm of my heartbeat) - so it's not a pain like I pulled a muscle or something. Now this pain will not go away.

When I'm laying down my head is slightly swollen, but it's not that bad. However if I get up and move around for the slightest amount of time it feels like my head swells up a great amount. Last night I had some serious involuntary shaking and extreme body aches the entire night.

I recently went to the emergency room and they said I had what sounded like a migraine. They did a CT scan on my head and told me that they couldn't spot anything wrong. I took the medicine they gave me (imitrex) and it really didn't do anything for me.

My problem is gradually getting worse, and this is where it's taken me.

I currently have:

lack of interest in food (have to force myself to eat - I've already lost 25lbs)
head swelling pain
involuntary shaking all the time now
body aches (throughout body but mainly directly above both knees)
vomiting (did earlier this morning, although there was nothing to throw up)

I have been constantly checking my temperature and it hasn't gone up (which I find odd). Bright light doesn't seem to bother me either (which leads me to believe I do not have migraines) . Sounds however do bother me, mostly somewhat loud and abrupt ones.

How about a pheochromocytoma? It's a tumor in or outside of the adrenal gland and can cause sharp rises in blood pressure which can force too much blood to your brain and make it throb. Weight loss, headaches, shaking, nausea, and flank pain are all symptoms. You are better off not going to the ER since they only usually treat the obvious. You need to see a doctor who can work with you to get to the bottom of this!